Concerning Ziegler-Natta type catalysts which are effective in polymerizing olefins, catalyst components having transition metals deposited on various kinds of carriers have been developed for the purpose of improving catalyst activity per unit amount of catalyst or decreasing residues originating in catalyst and persisting in produced polymer.
Heretofore various methods have been tried for the preparation of catalyst components which have inorganic carriers such as silica and alumina held in contact with organic magnesium compounds and further have titanium halide compounds held in contact therewith. The catalyst components obtained by these conventional methods suffer from insufficient catalytic activity as their salient disadvantage.
Recently, a catalyst component obtained by causing hydrocarbyloxysilane to react upon a reaction product of a porous carrier such as silica and an alkyl magnesium compound and subsequently causing a titanium halide compound to react upon the resultant reaction product (U.S. Pat. No 4,335,016 assigned to Chemplex) and a catalyst component obtained by causing an organic metal compound to react upon a porous carrier, causing a hydrocarbyl alcohol to react upon the resultant reaction product, and then causing a titanium halide compound to react on the reaction product (U.S. Pat. No. 4,378,304 and 4,458,058, each assigned to Chemplex) have been proposed. Although these catalyst components exhibit improved catalytic activity, the polymers obtained by their use have insufficient bulk density and are therefore not desirable.